Name    TimeIn                      TimeOut

Bob     2012-07-17 07:00:00.000     2012-07-17 16:00:00.000
Sam     2012-07-17 10:00:00.000     2012-07-17 20:00:00.000
Beatly  2012-07-17 14:00:00.000     2012-07-17 23:00:00.000
Mac     2012-07-17 21:00:00.000     2012-07-18 07:00:00.000

Name    TimeIn                      TimeOut
Fred    2012-07-17 15:59:00.000     2012-07-18 00:19:00.000

DirName HelperStart                 HelperEnd
Bob     2012-07-17 15:59:00.000     2012-07-17 16:00:00.000
Sam     2012-07-17 15:59:00.000     2012-07-17 16:00:00.000
Beatly  2012-07-17 15:59:00.000     2012-07-17 16:00:00.000
Sam     2012-07-17 16:01:00.000     2012-07-17 20:00:00.000
Beatly  2012-07-17 16:01:00.000     2012-07-17 20:00:00.000
Beatly  2012-07-17 20:01:00.000     2012-07-17 21:00:00.000
Beatly  2012-07-17 21:01:00.000     2012-07-17 23:00:00.000
Mac     2012-07-17 21:01:00.000     2012-07-17 23:00:00.000
Mac     2012-07-17 23:01:00.000     2012-07-18 00:19:00.000

select d.name as DirectorName, h.name as HelperName,
       (case when d.timeIn > h.timeIn then d.timeIn else h.timeIn end) as HelperStart,
       (case when d.timeOut > h.timeOut then h.timeOut else d.timeOut end) as HelperEnd
from director d join
     helper h
     on d.timeIn < h.timeOut and
        d.timeOut >= h.timeIn